My first reaction as I pulled up to the 2016 Red Bull Rampage course in the mountains of Virgin, Utah, outside of Zion National Park was, "No human can ride a bike down that."

I envisioned myself over 700 feet up at the top of the courseâwhich was recently carved into a jagged cliffâand immediately tumbling to my death.

Fortunately, I wasn't doing any mountain biking. That would be left up to 21 of the best mountain bikers in the world. Not only are they the best of the best, it would simply not be safe to have a larger field competing on such a dangerous course.

My first reaction as I pulled up to the 2016 Red Bull Rampage course in the mountains of Virgin, Utah, outside of Zion National Park was, "No human can ride a bike down that."

I envisioned myself over 700 feet up at the top of the course—which was recently carved into a jagged cliff—and immediately tumbling to my death.

Fortunately, I wasn't doing any mountain biking. That would be left up to 21 of the best mountain bikers in the world. Not only are they the best of the best, it would simply not be safe to have a larger field competing on such a dangerous course.

Red Bull Rampage is an annual competition in which mountain bikers perform a freestyle downhill run similar to freestyle skiing and snowboarding. The riders are judged on the difficulty of their course and the tricks, which are inspired by BMX, that they execute along the run.

"We are looking for line choice, difficulty of that line, progression, amplitude, style, fluidity and control kind of mixed together," says Randy Spangler, head judge. " It's an overall impression of the run from top to bottom."

The riders create their own lines down the course by building their own unique jumps, ramps and drops. Each competitor has a team of two who help build their course several days in advance of the competition. Typical features include steep drops, jumps over canyons and large ramps for crazy tricks.

"The one thing people don't realize is how much work it takes to build these lines," explains Darren Barrecloth, who has competed at Red Bull Rampage since 2002. "We don't just roll out here and ride down these hills. We spend hours and hours and days shoveling these landings and making it so we can ride down these hills."

For this year's event, they returned to the roots of the event, only allowing only dirt jumps supported by sandbags, whereas in previous years the riders could build wooden jumps.

I arrived two days before the event and had the chance to check out the course before it was finished. I hiked up to the top where the riders would start their death-defying runs, and was fairly terrified.

The hastily carved trail to the top was no more than 2 feet wide with a steep cliff to the side. It would serve as primary path for the competitors, crew and haulers who had to carry the bikes to the start of the course.

When I looked down on the course, it seemed impossible to navigate—there were portions with a several-hundred-foot drop on each side of a narrow path. Yet, the competitors would be cruising down at high speeds, integrating tricks wherever possible.

"This is about as scary and extreme as it gets for our sport," says Spangler.

During the day before the event, the riders practiced each section of their line individually. They carefully calculated the speed they would need to execute the section, and marked blind jumps with rocks so they could hit the jump with the correct angle to make the landing.

Understandably, we were told never to touch these rocks.

The competitors focused their practice on the bottom portion of the course. It's less dangerous and they could build their confidence before heading up the mountain. Some only took one run from the top, knowing they were putting their lives on the line.

"The most challenging part of riding the lines definitely is guinea-pigging, which is hitting things for the first time because once you hit it, you're like 'OK, I know how fast to go, I know what to do'," says Barrecloth.

Although they may appear fearless, each rider is well aware of the danger ahead, as shown by Claudio Calouri who hilariously narrates a practice run in the video below.

Behind the scenes, the Red Bull TV crew sets up a massive operation to capture every dramatic moment during the event. Cameramen are scattered around the mountain, and a helicopter with a camera is a constant presence, hovering over the course for epic overhead shots. We were told it's an operation similar in scale to Sunday Night Football, but with more confined and challenging conditions, given that the event is in the middle of a desert on a mountain.

On competition day, 2,000 avid fans filed into the sold-out event and set up camp on adjacent ridges and hills, anxiously awaiting their favorite competitors to hit their lines.

At this point, the riders were completely dialed into their lines. Some went for high speeds and bigger tricks while others went for more technical runs and big drops in a quest for the maximum of 100 points.

There was a fairly strong wind, which the riders explained can be a major problem. Once in the air, their bikes act like a sail and even a small breeze can knock them out of position. When there are steep drops and cliffs, this is obviously a concern.

However, the event went on as planned.

We witnessed some jaw-dropping feats of athleticism with 360s off sheer cliffs and even a double backflip. Unfortunately, Graham Agassiz took a hard fall that resulted in a fractured pelvis, but he is recovering successfully.

Most impressive was the mental toughness of these riders. I'm still not sure how it's possible to build the courage to ride such an intense and dangerous course.

Image via Bartek Wolinski/Red Bull Content Pool

Although there were some incredible performances, Brandon Semenuk, previous Red Bull Rampage champion, took home the title with a what was described as a near-perfect run. Antoine Bizet and Carson Storch came in second and third place, respectively.